1. PFO and Decompression Illness in Recreational Divers
Joel Silverstein, STT Inc.

2. PFO and Decompression Illness
What a PFO is.
Who has them.
What affect does it have on DCI?
What other risks does it pose?
Should it be fixed ?
Case Studies.

3. Patent Foramen Ovale (PFO) (hole in the heart)
A patent foramen ovale (PFO) is a defect in the septum (wall) between the two upper (atrial) chambers of the heart.
The defect is an incomplete closure of the atrial septum that results in the creation of a flap or a valve-like opening in the atrial wall
A PFO is present in everyone before birth but seals shut in about 75% of people

5. With each heart beat or when pressure is increased in the chest the flap can open and blood can flow in either direction directly between the right and left chambers.
When blood flows directly it bypasses the filtering system of the lungs. If debris is present (either clots or bubbles) it can lodge in the brain, causing stroke, or in other organs such as heart, eyes, or kidneys.

6. PFO normally does not produce negative symptoms.
However in some...
Migraine Headaches
Stroke caused by blood clot
Decompression illness in divers
Arterial Gas Embolism in divers

7. How does it open up ?
The passage may open up under certain circumstances:
Coughing underwater
Valsalva movement to clear ears
Stretching out and expanding chest
Straining or work exertion
Rapid ascent and gas bubble expansion

8. animation

9. How is it diagnosed ? Normally not diagnosed until event occurs.
TIA – Transient Ischemic Stroke
Sudden weakness, numbness in face arm or leg
Difficulty speaking or understanding words
Blurred vision
Loss of balance
Loss of consciousness
Paralysis
For divers .... suspecting
Skin Bends
Decompression Illness
Arterial Gas Embolism

10. Diagnostic Testing TTE TEE Transthoracic echocardiography
Small amount of air is injected into a vein and is observed with an echocardiogram
detection in only 10-18% of population / about half that actually have PFO
TEE
Trans-esophageal echocardiography
Probe via esophagus after local and IV sedation
detection in 18-33% of population

11. Should divers be tested for PFO?
“There is no indication for a diver to have a routine screen for a PFO”
Alfred Bove, MD, Emeritus Prof. Temple U.
“No, PFO is so common and DCI so rare...”
Peter Germonpre’, MD - DAN Europe Medical Director
“It is difficult or impossible to ascribe a particular DCS occurrence to a PFO..” PFO testing is useful only in instances where there have been several DCS incidents”
Richard Moon, MD – Senior Medical Consultant DAN USA

12. Divers who have had repeated issues of skin bends and other minor cases of DCI who test positive and repair PFO or modify diving activity eliminate future undeserved DCI
Dr. Douglas Ebersole
prompts need for five-year study

13. On site – DCS monitoring
For years Doppler bubble studies have been done on recreational diving and “flying after diving” protocols
UCSD hyperbaric department teamed up with a group of San Diego deep divers to do on-site monitoring....

14. UC-SD on site DCS monitoring
UCSD gatherd data on-site – from deep 280’ and 250’ dives earlier this year.

15. Echo on diver who presented symptoms of DCI post 250 fsw dive

16. Echocardiogram
DOPPLER AUDIO

17. “During my first echocardiogram the right side of my heart was full of bubbles and I noticed a burning sensation moving across my back. I was bent....
The Dr.s on board were very excited as I would be the first one in the world to have my DCS documented like this.
We were able to see the bubbles moving from the right side to the left side of the heart as the body could no longer filter out all the helium and nitrogen.”

18. Causes of Decompression Illness
Missed decompression stops - causes excessive bubble formation, which overwhelms the pulmonary filter to reach the systemic circulation (Provocative dives)
Rapid ascent - causes pulmonary barotrauma with gas invasion of pulmonary veins (Often conservative dives)
Right-to-left shunts – (PFO) venous bubbles by-pass the pulmonary filter (Dives of intermediate severity)

19. PFOs and decompression illness
A right to left shunt is usually across a foramen ovale (PFO).
Paradoxical gas embolism causes neurological, cardiovascular and skin decompression illness (DCI).
It causes 52% of neurological DCI (75 subjects in study). (Clinical Science 2000;99:65-75)
It causes 78% of skin DCI (75 subjects in study). (Clinical Science 2001;100: )

20. Classic Bends (DCI – Type I)
Localized deep pain ranging from tingle to excruciating
Dull ache or sharp pain
Localized in joints:
elbow, shoulder, hip, wrist, knee, ankles
If caused by altitude pain can occur immediately our hours after ascent

21. Skin Bends Mild form of decompression illness which presents with:
Itching, around face, neck, ears, arms, and upper torso
Sensation of tingling over skin
Mottled or marbled skin around shoulders and upper torso with or without sensation
Swelling of the skin, with scar-like skin depressions.

22. “SKIN” BENDS

23. Neurological DCI (Type II)
Brain
Memory Loss, Headache, Visual Disturbances
Spinal Cord
burning, stinging, tingling
bi-lateral movement via extremities
Extreme Fatigue / Behavioral Changes
Paralysis
Peripheral Nerves
Incontinence (urinary and fecal)
Paresthesia
Inner Ear
Loss of Balance, Extreme Vertigo, Hearing Loss

24. Many divers who have repeated cases of skin bends and are then tested for PFO are shown to be positive for PFO

25. Arterial Gas Embolism (AGE)
Pulmonary Barotrauma
gas bubbles enter bloodstream as a result of gross trauma to the lining of the lung following a rapid ascent.
bubbles in the bloodstream can form clots and precipitate stroke.
gas bubbles can form in arterial system and travel and lodge in the brain where they can cause stroke.

26. Causes of decompression illness
SHUNT
LUNG
DIVE
CNS
52%
26%
16%
CVS
ABOUT 1/2
ABOUT 1/4
SKIN
78%
22%
JOINT ?0
?100%

27. What is required for shunt mediated DCI?
A large right to left shunt.
Dive profile liberates venous bubble.
Dive profile causes an appropriate inert gas load in critical tissues to amplify embolic bubbles.
(Note -DCI does not occur after contrast echocardiography)

28. Prevalence and size of shunts
27.3% of population have a PFO. (Mayo Clinic Proc 1984;59:17-20)
27 .6% of controls have a shunt but
only 7.3% are large –
4.9% at rest
2.4% only with Valsalva.
(Clinical Science 2000;99:65-75)
Risk of DCI is related to shunt size.

30. Closing a PFO in a diver who had decompression illness
The shunt must be large and history specific.
Confirm that DCI was not the result of lung disease or a provocative dive.
The options are to stop diving or to have transcatheter closure of PFO (or ASD) or, if amateur, to modify diving to reduce nitrogen load.
Check that there is no significant residual shunt before return to diving after PFO closure.

32. 32

33. Sub-atmospheric decompression illness
During hypobaric experiments 6-39% of subjects have heavy venous bubbling.
Serious DCI is sometimes encountered. There is usually a resting PFO.
Insufficient numbers to be sure about the role of PFO (or other shunts) in sub-atmospheric DCI, but enough evidence to advise that those with shunts should not be astronauts.

34. The link between migraine and decompression illness
Known since 1944 that individuals with migraine with aura have increased risk of neurological DCI. (War Medicine 1944;5:304-14)
Post dive migraine aura is virtually diagnostic of a large shunt and indicates increased risk of DCI. (Clinical Science 2001;100: )
Migraine with aura can occur after contrast echocardiography in those with a large shunt.

35. Right to left shunts and migraine with aura
Using transcranial Doppler it was shown that right to left shunts are present in 41-48% of patients with migraine with aura, 23% of those with migraine without aura and 16-20% of controls (p < 0.01).
(Del Sette et al. Cerebrovasc Dis 1998;8: & Anzola et al. Neurology 1999;52: )

36. Migraine with aura linked to right-to left shunts
52.9% of divers with large shunts at rest have migraine with aura in every day life v 11.8% of divers without shunts.
There is a size-prevalence relationship.
Migraine without aura is not related to the presence of a shunt.
Post dive migraine aura is virtually diagnostic of a large shunt.
(Clinical Science 2005;108: 365-7)

37. Case #1 Migraine - AGE - PFO
June 2006
36 Y/O Female
Suffers serve AGE
benign dive with complete decompression
seven seizures on deck
coma ten days
rehab for 18 mos
April TEE PFO Test
“massive bubbling”
PT was treated for DCI 3 years earlier after open water dives – was suggested to be tested for PFO but ignored it.
complains of severe migraines for more than 4 years prior to incident – post incident pt reports migraines had gotten worse for 3 months prior to incident.

38. PT today has 25% cognitive and physical deficits, uses wheelchair.
Had PFO repaired – migraines gone

39. Case # 2 Skin Bends since 1967 22 Y/O Female
suffers skin bends after 190 fsw dive to Andrea Doria
Between 1967 and 1992 presents more than 75 times with “skin bends”
1992 Shifts to nitrox and pure oxygen for diving – skin bends disappears
Air diving in Carib and South Pacific and skin bends re-appears

40. Gets Diagnosis and Repair
At age 65 Evelyn Bartram Dudas gets PFO test, found positive and repairs.
“Medicare covered it all, and to think I complained about this all these years and it’s just a tire patch.”

41. Case # 3 Skin Bends 51 y/o Female excellent condition
dives dives a year
long dives 90 + min
extensive DPV use – minimal exertion
frequent repetitive shore and boat dives
Air / nitrox diving

42. 2007 begins doing longer dives nitrox 32% most dives
800 dives total, minimum deco, not many repets – no symptoms – air only
2007 begins doing longer dives
nitrox 32% most dives
dry suit and large tanks for longer bottom times
extensive DPV use extends SAC extending dives
Skin bends occurs (age 48) after 3rd and 4th dive of day when using air only
Added 50% nitrox for deco continues to have skin bends a few x per year
Mid 2009
1250 dives total
Casually joined ongoing study to test for PFO with Trans-cranial Doppler
Result: Class 3 PFO.
Small, but consistently patent even without Valsalva elevation of intrathoracic pressure

44. Modified protocol
7day pause to evaluate situation. Decides not to repair since has no desire to dive deeper than 150 fsw / decompression minimal. But, decides to modify profile protocol extensively.
Highest reasonable nitrox mix for planned dives 28% to 40% oxygen
brings additional cylinders for boats with no nitrox
100% oxygen as deco clean up mix
minimum 6 min on no-stop dives and on all dives deeper than 60 fsw
High Oxygen Trimix
(21-30% oxygen 25% helium)
for dives fsw
Slightly shorter profiles with more conservative dive computer
Mid 2010
1450 dives total . max depth 150 fsw
One skin bends event in July 2009 when no o2 was used
No symptoms last 200 dives
If symptoms return on current protocols, PFO will get closed

45. Case # 4 Ocular Migraine/Skin Bends
32 Y/O Female
2001 first instance of diving related ocular migraine after 242 ft trimix dive. No skin bends
2003 two instances of ocular migraine and skin bends following a 172ft dive and 236ft dive.
2004 next instance of ocular migraine and skin bends after 200ft dive
2006 instances occurring more frequently

46. Symptoms and Treatment
Ocular migraine
Visual disturbance: small enlarging blind spot with shimmering zig-zag line lasting up to 30 minutes and moves between both eyes.
Would occur 15min -1:45hr post dive. If no symptoms 2hrs post dive knew I was clear
Lasts min and usually be followed by a migraine type headache
Skin Bends
Presented on left arm, shoulder and abdomen
Adipose tissue on thighs would ache
Treatment
Started O2 after visual disturbance presented
Duration dependent on symptom
10-30min usually
Advil (NSAID)
Fluids
Never went to the Chamber as symptoms would resolve
Side note: Headache sometimes lasted days.

47. Gets Diagnosis and Repair
At age 37, March 2006 gets PFO test, found positive and repairs Jan 2007.
PFO closed with 25mm Amplatzer
6 weeks post PFO closure returned to
recreational diving depths
6 months post PFO closure returned to tech diving depths and times
No ocular migraines or skin bends since

49. DAN PFO Project Purpose of Study Background How the Study Works
How People Volunteer
Preliminary Reports 49 49

50. Purpose of the Study Establish who is better-off Risk Estimation
Divers with PFO who undergo closure
Divers with PFO who do not close it
Risk Estimation
Will be based on combined incidence of adverse events due to decompression and due to the closure procedure.
Risk/Benefit Estimation will be based on comparison of incidence of DCS both before closure and after closure.

51. How the Study Works. Trial Enrolls 120 Qualified Participants.
Annual Follow-up for 5 years.
18 years or older.
Certified Diver with Medical Clearance.
Undergone Trans-Catheter PFO Closure or
Diagnosed PFO

52. Orientation of Participant
Full disclosure of Study
Informed Consent
Complete Diving History Questionnaire
Provide Medical Documentation of:
Diagnosis of PFO
Closure of PFO
Any future tests are also reported back to the study.

53. Over Next Five Years
Participant dives according to their own schedule / plan.
Maintain Logs of all dives completed.
Provide electronic data from dive computers or rebreather download for research
Report how they feel post dive.
Project started Spring 2011

54. Baseline Questionnaire
Age, Sex, Weight, Height
Certifications Held
Dives done prior to diagnosis
Dives done post diagnosis
Dive done post closure
How did you plan dives prior to closure or diagnosis?
How do you plan dives now ?
Allows the researchers to compare similar items and monitor changes in the study subject yearly.

55. Baseline questionnaire . cont.
History of DCS?
Fatigue
Headache
Migraine with Aura
Skin Itching / mottling
Dyspnea
Loss of consciousness
Loss of vision
Vertigo
Pain in joints / muscles
Swelling
Breast Pain
Numbness / Tingling
Abdominal Pain
Muscular Weakness
Paralysis
Inability to Urinate
Confusion
Disorientation
Memory Loss
Loss of balance
other

56. Health History High Blood Sugar or Diabetes Insulin ?
Heart Attack (MI) ?
Coronary Heart Disease ?
Stroke?
Heart Disease Rx?
Heart Surgery ?
Pacemaker ?
High Cholesterol ?
Levels ?
High Blood Pressure ?
Physical Impairments ?
Any health problems that caused you to use special equipment ?
Have you smoked at least 100 cigarettes in your life?
Smoke now?
How often?
Alcoholic Beverages?
How much?

57. Preliminary Findings
Retrospective survey of scuba divers diagnosed with PFO in various clinical centers.
Explored the number of episodes of DCI
Clinical aspects of DCI manifestation.
Diving practices of the subjects.
Reported magnitude of right-to-left shunt.
Differences between groups were tested with Fisher Exact test. Significance was accepted at p<0.05.

58. Initial Results 30 Divers Diagnosed
19 had repeated episodes of DCI prior to diagnoses
8 had only one episode
3 had PFO diagnosis with no DCI
16 presented with multi-organ symptoms
skin, cerebral, pulmonary, vestibular DCI
6 had single organ symptoms
2 vestibular, 2 skin, 2 spinal cord
5 had ambiguous symptoms
2 mis-diagnosed

59. Initial Results cont. 2
20 divers practiced regular deep and decompression diving.
1 professional commercial diver
8 recreational no-stop dives only
Magnitude of left-right shunting
could not be measured due to variations of testing methods

60. Initial Results cont. 3 Diving Practices
no dramatic difference between divers who had closed PFO and those who did not.
Repetitive and Multi Organ DCI
more common in closure group
18/19 vs 4/11
Five out of Six Divers
diagnosed with PFO underwent closure
One with Ambiguous symptoms
insisted on Closure to be eligible for GUE training

61. Conclusions
All Divers in Closure Group had a history of repetitive or multi organ DCI
PFO is contributory to their repeated DCI episodes
Decompression vs. no-decompression diving had little effect on outcome
More work to be done.

62. Summary PFOs exist in up to 30% of population Land based small risk
sizes vary from small to large
Land based small risk
Diver increased risk:
AGE, Neurological DCI, Skin Bends,
Repair relatively easy but still invasive with measurable risks
May be able to modify dive protocol to minimize risk of DCI event

63. Risk of Injury by Categories of Divers
Recreational divers –
small risk if asymptomatic
decrease bottom times, limit depth, cut back no-stop times, slow ascents, use nitrox
Active Enthusiasts –
increased risk if symptomatic
above plus use multiple mixes and oxygen to reduce risk further
Technical Diver – high risk
good candidate for repair
Commercial Diver – contraindication
candidate for repair or stop diving

64. Should you test? Personal choice DCI from non provocative dives
good candidate
Active enthusiast, doing big & long dives and experiencing symptoms
Working diver with known DCI
Just curious ?
not good candidate

66. References PFO and Decompression Illness in Recreational Divers
Alert Diver Spring, 2010
PFO Update - Dr Peter Wilmshurst
UK Sport Diving Medical Committee and Royal Shrewsbury Hospital
PFO Animation courtesy CardioSEAL – Cleveland Clinic Foundation
14th Nordik Stroke Conference
Kristian Emmertsen Dept of Cardiology Aarhus University Hospital, Skejby
Tech Diving Limited - Case Study Interviews 2010, 2011

67. References Cotton, JB Ebersol, DG Pollock, NW Denoble, PJ
Our World Underwater Scholarship Society,
Ebersol, DG
Watson Clinic, LLP, Lakeland, FL
Pollock, NW
Denoble, PJ
Divers Alert Network, Durham, NC
Duke University Medical Center 67 67